Amplifying-receiver.



E. s. PmoaAM'aE P. L. JENSEN.

AMPLIFYING RECEIVER.

APPLICATION FILED IULY 3.19.

1,266,988. Patented May 21, 1918.

2 SHEETS-SHEET K I l I' I WITNESS:%

Patented May 21,1918.

7 IIIIIIIIIIII I lllll II INVEN'TOR .Eolwen ,IS'LPrZcZVzam .Efer L 671912-9622 Bag/fl WWW UNITED STATES A CORPORATION 01? ARIZONA.

or NAPA,

& DEVELOPMENT CO., OF SAN FRANCISCO, CALIFORNIA,

AMPLIFYING-RECEIVER.

Specification of Letters Patent.

Patented May 21, 1918.

Application filed July 3, 1918. Serial No. 107,448.

To all whom it may concern:

Be it known that we, EDWIN S. PRIDHAM and PETER L. JENSEN, both citizens of the United States, residing at N apa, in the county of Napa and State of California, have invented new and useful Improvement in Amplifying-Receivers, of which the following is a specification.

This invention relates to amplifying receivers of the type shown and described in our Patent, No. 1,051,113, dated January 21, 1913, for use in telephony, and has for its object to simplify and improve the construction and operation of such devices.

In amplifying receivers of this type, a. conducting coil for telephonic currents, is disposed in a magnetic field so as to cut transversely the lines of force of the field, whereby a force acts upon the coil, to vibrate the same at right angles to the magnetic force, the magnitude of the vibrating force being the product of three factors, namely, the length of the conductor perpendicular to the lines of force of the ma et, the strength of the magnetic field, and the strength of the current flowing through the conducting coil. By making the magnetic force great and disposiu a great length of the conductor to the influence of the magnet, vibrations of the coil may oe roduced to actuate a diaphragm for re rod iicing sound waves of considerable amp itude, even where the strength of the telephonic currents is com paratively weak.

It is therefore important, in order to prodoes an intense magnetic field, to have a very narrow air gap between the pole pieces of the magnet and also the greatest possible len h of conductor exposed in the magnetic fiel and at the same time restrict the size and weight of the coilwithout impairing its rigidity. The form of coil here' rovided, will present a maximum length 0 wire to the magnetic force, is light, thin and affords the desired rigidity for imparting all its vibratory movements to the diaphragm to which it is attached. Other novel and advantageous features of the present device will become apparent upon a further understanding of the invention.

0116 form which our invention may asvibrating coil attached sumo is exemplified in the following description and illustrated in the accompanying drawings in which- Figure 1 shows a side elevation of the device embodying our invention, certain parts being broken away to show the interior construction.

Fig. 2 shows a plan view of the bottom of e same.

Fig. 3 shows a perspective view of the novel form of conducting coil employed in our device.

Fig. 4 shows a similar view, disclosing a slight modification.

Fig. 5 shows a cross sectional view of the coil.

Fig. 6 shows a diagram of the electrical connections employed in the device.

Fig. 7 shows a side elevation of a portion of the device, with the casing in section.

Fig. 8 shows a plan view of the magnetic pole pieces with the sound box and vibrating coil in position thereon.

Fig. 9 sh of the sound box and diaphragm with the thereto, and

Fig. 10 shows a sectional view on line 10-10,Fi .7.

In the rawings, a receiver is shown as comprising a casing 10, within which is an electro-magnet 11, preferably of the horseshoe type and having pole pieces 12 directed toward each other and separated by a narrow air gap. Within this gap is our 1mproved coil 13, consistin generally of a large number of turns of ne wire approx!- mating an annular form, said wires being bunched at the back 14 andflattened or spread out at the front 15, thereby presenting a coil wedge-shaped in cross sectlon, as shown in Fi 5. The bundle of wires at the back side 0 the coil is secured together by means of tie wires 16. Mica or other nonconductin plates 17 are placed at opposite sides of t e coil and are preferably made smaller than the coil and arranged so that the bundle of wires at the back is exposed, projections 18 on the corners of the plates being provided to engage the sides of the bunched wires. A bracket-shaped clip 19 of light material, such as aluminum, is rigidly ows a plan view of the inner side secured to each plate 17 at the back side thereof, one of said clips bein held by a rivet or screw 21 passing throu the central portion of both plates and t e other clip being held by means 0 screws or rivets 21 one at either side of the central portion of the plates, said last mentioned clip being bifurcated at its inner end for this purpose. The clips 19 have flanges 22 at their outer ends, adapted to be rigidly secured to a receiver diaphragm 23 by means of screws or fasteners '24. The diaphragm 23 is stretched between plates 25 secured to the casing 10 and formin a sound box. Preferably a sorewthrea ed nozzle 26 is provided for the sound box to receive an earpiece or amplifier not shown.

The meta lic connections between the coil 13 and the transmission line are such as to prevent interference with the free vibration of the diaphra and coil and to obviate any danger o the connection becoming broken 'on account of the necessary vibrations which take place. One end oi the coil is connected to one of the posts 21 and the opposite end of the coil is connected to the post 20. Thin metallic strips 27 are glued to the diaphragm with shellac or other suitable substance and insulatin material 28 in addition to the shellac may laid between the metallic strips and the diaphragm; The said strips 27 are secured at their inner ends to the fasteners 24: on the diaphra and extend radially outward to the ,perip cry of the diaphragm where they are projected downwardly and attached to bindmgposts 29 secured to an insulating block 30 on the sound box. The brackets or clips 19 in the form shown in Fig. 3, mayserve as conductors between the metallic strips 27 and the coil, or separate wire connections 31 ma be made between these parts, as shown in g. 4, in which case the bifurcation on the end of one of the brackets ma be dispensed with and both brackets made i entical and secured in place by the cditrally positioned screw 20. 11 operating circuit for the receiver is shown in Fig. 6, as an illustration of one manner of operating the device. This circuit includes service mains 82 and 33, to which the wi ding 34 on the magnet is connect'ed, and also a storage 35 connected to said A multi contact controlling switch "36 is shown as located between the magnetic' winding and the storage hm." Transmitters 37 are shown as conn to the storagebattery 35 and to the prima induction c011 38, a return connec tion being had through the switch 36. ,The second of the induction coil is connected to the vi rating c011 13. f

The construction and arrangement offthe coil 13 go to make up a thin, rigid member with a maximum presentation of the conducting wire. As will be noted, the wire is spread out at the front portion of the coil, where it intersects the ma etic field, thereby exposing practically al of the turns of the mm to the influence of the magnet. The backportion of the coil, by having its wires bunched, forms a support for the entire coil, afiording the desired rigidity. The clips 19' obviously afiord a stron connection between the coil and iaphragm. By securing the thin, metallic conducting strips to the diaphragm, we overcome the diiiiculty presented in attaching a conductor to a vibratory member. The movement of the diaphragm at or nearits eri hery is obviousl sllght and therefore y astening the diaphragm at the con ucting strips to this point, there will be a minimum of bending action on the strips, with a consequent lessening of the danger of breakage.

Various changes 1n the construction and arrangement 0 the several parts herein shown and described, may obviously be em ployed, without departing from the spirit of our invention, as disclosed in the appended claims.

Having thus described our invention, what we claim and desire to secure by Letters Patent is- 1. In an amplifying receiver for telephony, a magnet having a narrow air-gap and a transversely movab e coil disposedin said air-gap and carrying telephonic currents and comprising a large number of annular turns of wire spread over a large area and forming a wide flat surface of such thinness as to require an external support.

2. In an amplifying receiver for telephony, a magnet having a horse-shoe core with its pole ieces extending inwardly and spaced a s'lig t distance a art and a transversely movable coil for t e telephonic currents disposed between said ole pieces and comprising a large number 0 annular turns of'wire s read over a large area and forming a wi e flat surface, said coil conn to the diaphragm of the receiver, nections between the coil and the op circuit comprising thin metallic strips.

3. In an ampli 'ng receiver for telephony, a magnetic fie d and a conducting c'oil for telephoniccurrents di therein and iaph rigidly attached to the ragm of the receiver, said coil com rising a large number of annular turns 0 fine wire having the portion disposed in the field spread over a flat surface and the o posite portion bunched-to form a support or the coil.

4. In an ampli g receiver for telephony, a magnetic field and a conducting coil for telephonic currents disposed therein and rigidly attached to the iaphragmof the receiver, said coil comprising alarg'e numand and concrating *1 her of annular turns of fine wire having the portion di osed in the field spread over a flat an ace and the opposite portion bunched to form a support for the coil, insulating plates on the opposite sides of said coil, secured together, and binding posts on said plates to receive the ends of the coil.

5. 11 an amplifying receiver for telephony, a magnetic field, a conducting coil for the tele honic currents disposed in said field an comprisin a number of annular turns of fine wire avin the portion disposed in the field sprea over a wide fiat surface and the o posite portion bunched to form a support or the coil, and bracketshaped clips for attaching said coil rigidly to the diaphragm of the receiver. 15 6. In an amplifying receiver for telephony, a magnetic field, a conducting coil for the telephonic currents disposed in said field and comprising a number of annular turns of fine wire having the portion dis osed in 30 the field spread over a nude flat sur ace and the opposite portion bunched to form a support for the coil, bracket-shaped cli s for attaching said coil rigidly to the diap ragm of the receiver and connections between the ends of said coil and the clips.

7. A conducting coil comprising, a large number of annular turns of fine wire with the portion at one side spread over a wide fiat surface and the ortion at the opposite side bunched to ibrm a rigid sup ort for the coil, insulating plates secured to opposite sides of the coil and brackets secured to the plates for mounting the coil.

8. In a receiver for telephony the combination with a sound box'and its diaphragm, of a magnetic field, a vibrating conducting coil for the telephonic currents disposed in .said field, and rigidly secured to the diawith an operating circuit, comprising thin metallic strips secured at their inner ends to the diaphragm by said coil fastening means and extending outwardly along the surface of the dia hra to a point near the periphery thereo an stationary means for receiving the outer ends of said strips.

In testimony whereof we have hereunto set our hands in the presence of two subscribing witnesses.

EDWIN S; PRIDHAM. PETER L. JENSEN. Witnesses:

Jorm H. Humane, W. W. HEALEY. 

